shnitzl
off to a rocking start
Member since December 2016
Posts: 10
|
Post by shnitzl on Jan 13, 2017 12:28:00 GMT -5
I am looking to make my own setup to melt metal and cast objects. I have a natural gas outlet available in the backyard and that seems like the convenient way to go.
however I am not to certain on the burner assembly, couplings etc. would the membership have any guidance for me?
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 3,774
Member is Online
|
Post by gemfeller on Jan 13, 2017 14:47:50 GMT -5
Are you asking about a burn-out oven for castings or a melting torch? The two would have different requirements.
|
|
shnitzl
off to a rocking start
Member since December 2016
Posts: 10
|
Post by shnitzl on Jan 13, 2017 15:57:46 GMT -5
I suppose it would be the melting torch you put into the foundry, I'm new to this so my terminology could be wrong.
|
|
gemfeller
Cave Dweller
Member since June 2011
Posts: 3,774
Member is Online
|
Post by gemfeller on Jan 13, 2017 17:30:45 GMT -5
Please explain what you mean by the word "foundry." Are you thinking of casting jewelry-sized items or larger pieces like small statues, etc.? Foundries are usually devoted to large-scale castings of things like statues, bells, etc. Jewelry casting uses the same principles but on a smaller scale, with specialized equipment.
This video doesn't discuss gas connections but I found it interesting, Maybe it'll give you some ideas.
|
|
|
Post by pauls on Jan 13, 2017 19:21:02 GMT -5
Have a poke around in this forum, alloyavenue.com/vb/forum.phpjoin up, ask questions, they are a good bunch of people. Just about everything you need to know to melt metal.
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Jan 14, 2017 20:28:40 GMT -5
I am looking to make my own setup to melt metal and cast objects. I have a natural gas outlet available in the backyard and that seems like the convenient way to go. however I am not to certain on the burner assembly, couplings etc. would the membership have any guidance for me? Natural gas is supplied at a very low pressure. The flow rate will not provide enough BTU/HR to achieve all but modest temperatures. I doubt it would even melt aluminium. What is your goal? Look into propane and use the high pressure regulators. The ultimate is a combo HP propane and automotive oil burner. Start it up with propane then when cherry red start burning the fuel oil to achieve sincere "foundry" temps. What are you trying to achieve?
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on Jan 14, 2017 20:34:12 GMT -5
Have a poke around in this forum, alloyavenue.com/vb/forum.phpjoin up, ask questions, they are a good bunch of people. Just about everything you need to know to melt metal. Well done Paul! Thanks for the link.
|
|
ziggy
spending too much on rocks
Member since June 2016
Posts: 483
|
Post by ziggy on Jan 14, 2017 23:07:37 GMT -5
I am looking to make my own setup to melt metal and cast objects. I have a natural gas outlet available in the backyard and that seems like the convenient way to go. however I am not to certain on the burner assembly, couplings etc. would the membership have any guidance for me? I think what you are looking for is something like what is shown in the following TWO videos. The first video shows how to make the foundry (rock bottom cost uses sand and plaster of paris, (I would go with cast able refractory cement) and the second one shows how to run it on propane including building the burner from scratch. Ditto on what shotgunner said about the natural gas. Go with propane, or if you can afford a little extra cost, MAPP gas burns hotter than propane and might be hot enough to melt steel in this setup. Hubby is planning on making this setup to melt his scrap copper and recycle it into jewelry.
|
|
|
Post by pauls on Jan 15, 2017 0:09:06 GMT -5
Ziggy Your husband needs to go to Alloyavenue (http://alloyavenue.com/vb/forum.php). Melting and doing anything useful with copper is quite tricky and requires a fairly sophisticated burner and well built furnace to get to the required temperatures.
|
|
|
Post by pauls on Jan 15, 2017 5:54:13 GMT -5
A bit more time for a proper reply to ziggy.
The recipe in that video using plaster and sand for the refractory cement is just stupid. Probably useless after using it once. The same goes for most of the homebrew refractory mixes. At high temperatures things like cement and plaster act as fluxes and help the melting of the rest of the ingredients in your refractory. Aluminium, Lead, Pewter can use some of the better homebrew refractories without failing, for a while. Its much better to spend the money and buy a few bags of commercial pourable refractory, you will save money in the long run.
For copper you must have high temp refractory, a graphite or silicon carbide crucible and a way of getting things really hot. Copper will also require a charcoal blanket over the melt to stop everything oxidising. I did say its tricky.
At "alloyavenue" you will find plenty of ways to make a good workable propane burner, but for the hottest temperatures you probably need an oil burner running on oil obtained at the right price (free)from your local takeaway or auto workshop, Yep thats right you can melt metal with potato fryer oil and sump oil, any old oil will do. The burner is basically a tube through the side of the furnace (Tuyere)with a blast of air from a hair dryer or the back end of a vacuum cleaner. oil is dribbled into this tube and the oil air mixture enters the furnace and burns. There are plenty of fancy designs that preheat things with propane. My furnace is started with a piece of paper and some wood chips and twigs, when they are burning fiercely I turn on the oil, the oil hits the burning twigs, theres a woomph and then it starts roaring, a very satisfying sound. In minutes the inside of the furnace will be white hot. Anyone familiar with combustion knows that your lawnmower wont work if the carby mixture is wrong, too much fuel and you flood it, too little and its too lean and stops, same with the furnace. About a gallon an hour is around about right in mine, more fuel and I need more air and things start getting really loud and hot.
Casting metal is a whole nuther hobby but its potential is really up to your imagination, I have cast backing plates, laps, bearing housings, a part for my faceting amchine, lots more. In aluminium as its relatively easy, I did try copper but struggled to get it melted hot enough to pour, just enough to puddle in a semi melted sludge in the bottom of a expensive crucible and then go solid, of course when you try to heat it up again the metal expands and shatters the crucible. Grr.
|
|
ziggy
spending too much on rocks
Member since June 2016
Posts: 483
|
Post by ziggy on Jan 15, 2017 9:12:34 GMT -5
A bit more time for a proper reply to ziggy. The recipe in that video using plaster and sand for the refractory cement is just stupid. Probably useless after using it once. The same goes for most of the homebrew refractory mixes. At high temperatures things like cement and plaster act as fluxes and help the melting of the rest of the ingredients in your refractory. Aluminium, Lead, Pewter can use some of the better homebrew refractories without failing, for a while. Its much better to spend the money and buy a few bags of commercial pourable refractory, you will save money in the long run. For copper you must have high temp refractory, a graphite or silicon carbide crucible and a way of getting things really hot. Copper will also require a charcoal blanket over the melt to stop everything oxidising. I did say its tricky. Casting metal is a whole nuther hobby but its potential is really up to your imagination, I have cast backing plates, laps, bearing housings, a part for my faceting amchine, lots more. In aluminium as its relatively easy, I did try copper but struggled to get it melted hot enough to pour, just enough to puddle in a semi melted sludge in the bottom of a expensive crucible and then go solid, of course when you try to heat it up again the metal expands and shatters the crucible. Grr. I will address your comments in order. Yes, I already understand that sand and p.o.p. are not suitable and IF YOU WOULD HAVE READ MORE CLOSELY WHAT I HAD TO SAY you would have seen that I MENTIONED THAT CAST ABLE REFRACTORY CEMENT WOULD MAKE A MUCH BETTER SUBSTITUTE. Seems to me that is the EXACT SAME THING YOU SAY will work better. In the first video he is just using charcoal and forced air to operate his forge. Obviously this is not the way to go when trying to melt copper so if you would have watched the second video you would have seen that there is an alternative to that that is entirely capable of doing it. I wrote that stuff late at night right before going to bed. I was going to, first thing in the morning, make another entry here suggesting that instead of that stupid fire extinguisher crucible he purchase something more like Copper melts at 1, 984 degrees. These temps are easily obtainable using mapp gas (flame temperature of 2925 °C (5300 °F) in oxygen, combustion temperature of 2,020 °C (3,670 °F) in air.) and the propane burner setup. (Also as previously mentioned.) Mapp gas is so hot that it can be used for fusion welding on steel but not on anything too big. The home made burner can be made into a non oxidizing flame. The adjustable air inlet feature allows fine tuning of the flame and can perform as well as the "oil spray" type. It too is fed into the forge through the side and doesn't require any extra "hair dryer" or "vacuum cleaner" to get the correct air/fuel mixture. Being completely familiar with combustion I can see advantages of the simple to build propane/mapp setup over the complicated oil burning setup. There is always more than one way to skin a cat they say. The "old fashioned way" is not always the only way. Hubby told me to inform you that the problems you have with copper hardening quickly and breaking the crucibles is due to not melting enough copper to stay molten long enough to pour. With copper, more stock in the crucible and more time in the heat is all that is required after melting to obtain a successful pour. He also mentioned that your inability to get enough heat points to bad burner (read as air/fuel) adjustment. If you pull your crucible and it isn't glowing as bright as the molten copper, then it's not hot enough. Following is an example of someones backyard forge (powered by propane even) doing what you say can't be done. Hubby is no spring chicken and he for sure isn't stupid. He used to re-line a refractory furnace that was used to temper spring steel. He knows a lot about this stuff. He is almost 62 years old and has done more things in his life than anyone I've ever met. He is what I would call a mechanical genius. He spent his whole adult life professionally building huge machines and doing mechanical design. Has a college degree in computer network engineering (Cisco Certificate, not easy to obtain) that he never even needed to use. I originally posted to try and help the person who asked about making a forge. That simple design looked like a good start for him. Hubby plans on using just the burner design from the second video and has his own design for the actual forge itself. I think he won't have too many problems that he can't overcome.
|
|
shnitzl
off to a rocking start
Member since December 2016
Posts: 10
|
Post by shnitzl on Feb 1, 2017 23:05:24 GMT -5
Hi Everyone, okay lots of info here, I was away for awhile but I just wanted everyone to know I will use this as a start to my research. I am familiar with the refractory and will make this a proper set up to cast usable parts, I should had mentioned not for jewelry making sorry!
natural gas idea is scrapped, I suppose there are reasons why I always see propane used.
lots of help always ready and waiting on this forum, its awesome!
|
|